What do you mean by olefin? Give an example.

(N/A) Alkenes are commonly referred to as olefins,a term derived from the phrase 'oil-forming'. This name originated because the first member of the series,ethylene or ethene $(C_{2}H_{4})$,reacts with chlorine to produce an oily liquid,$1$,$2$-dichloroethane. Example: Ethene $(CH_{2}=CH_{2})$.